One example of conventional liquid crystal device has a construction in which a U-shaped reflecting plate is disposed in such a manner as to surround a fluorescent tube in a U shape and liquid crystal display element is disposed on a light diffuse-transmission plate that bridges over the open enexample, in Japanese Patent Laid-Open No. 155829/1984 entitled "Transmission Type Liquid Crystal Display Device" laid-open to public on Sept. 5, 1984.
However, if the light emission surface of the fluorescent tube itself is divided into a central portion and both end portions, the quantity of light (luminance) at both end portions is lower than that at the central portion. Accordingly, when the liquid crystal display device is arranged on an instrument panel of a car, for example, a fitting surface or the arrangement of the fluorescent tube must be examined carefully in order to prevent non-uniform illumination and to have the illumination averaged. Although the arrangement wherein a shade curtain is disposed between the light emission surface and illumination surface of the fluorescent tube to make uniform the light on the illumination surface has been put into practical application such as in billboards, this method involves the problem that the luminance at a low luminance portion can not be increased.
On the other hand, Japanese Patent Laid-Open No. 198850/1983 entitled "Light Source Using Mesh Heater", laid-open on Nov. 18, 1983 disposes a cylindrical mesh heater around the fluorescent tube in such a manner as to cover its light emission surface in order to ensure lighting of the fluorescent lamp even at a low temperature of below 0.degree. C. However, this mesh heater structure involves the problem that the luminance is not uniform in the longitudinal direction of the fluorescent lamp because the mesh is not a uniform grid.